uglifyjs drop_console / pure_funcs is not working in webpack - optimization

Question

I have the following configuration, but it still does not remove console.log statements:
new webpack.optimize.UglifyJsPlugin({
compress: {
warnings: false,
pure_funcs: ['console.log'],
drop_console: true,
comments: false
},
pure_funcs: ['console.log'],
drop_console: true,
comments: false
})
What am I doing wrong?

Answer 1

It's possible that the messages you are getting are debugging messages in the console, rather than console.log. I had a similar issue where I thought using drop_console would suffice. I had to add drop_debugger as well, so given your example, this should remove all console output.
new webpack.optimize.UglifyJsPlugin({
compress: {
warnings: false,
drop_console: true,
drop_debugger: true
},
comments: false
})

Answer 2

It is not the reason of uglifyjs in my case. It is caused by babel-loader which will transform console.log to (e = console).log.
I do not know how to fix it now. Finally, I have to use a babel plugin named babel-plugin-transform-remove-console to remove console.
However I do want to use UglifyJsPlugin.
This is a hint for those who can find out a resolution.

Answer 3

I had the same problem with drop_console not working in my react script setup (on Windows 10, React-script version 0.8.5).
Trying to reproduce this problem I created a brand new app, added console.log somewhere in App.js and drop_console: true in webpack.config.prod.js. However in this simple setup drop_console works and console.log is removed.
As it still didn't work in my real app I installed strip-loader:
npm install --save-dev strip-loader
then edited webpack.config.prod.js in node_modules\react-scripts\config (without ejecting from react):
var WebpackStrip = require('strip-loader'); // around line 20
...
// inserted in module/loaders between babel and style loaders, around line 168
{
test: /\.js$/,
loader: WebpackStrip.loader('debug', 'console.log')
},
Sure enough, all console.log statements were removed (npm run build). I then removed all my changes from the config and console.log were still being removed. I uninstalled strip-loader and the build still successfully removes console.log statements.
I cannot explain this behaviour, but at least it works (although somewhat magically).